Multisim 2001 (electronics workbench) simulation problem
rob
and have
hit a bit of a snag.
When I analise a circuit I'm using the oscilliscope function.I connect
the scope to the parts (2 points) of the circuit I want to analise and
run the simulation. So far so good.I get what I am expecting on the
screen.
Now the problem. I want to now check some other part of the circuit ,
I have to
delete the conections to the scope , re-draw them to the new points
and
re-run the simulation. This does not seen correct to me.Other
simulators(ie
LTspice) you just move the cursor around the schematic and click where
you want to see the waveform.
I am sure Electronics Workbench can do this , but I am sure I am
overlooking
something.
Any help would be appreciated.
Cheers
Rob
Kevin Aylward
> Hi to all. I am working with Electronics Workbench for the first time
> and have
Poor man.
> hit a bit of a snag.
Not surprising.
> When I analise a circuit I'm using the oscilliscope function.I connect
> the scope to the parts (2 points) of the circuit I want to analise and
> run the simulation. So far so good.I get what I am expecting on the
> screen.
> Now the problem. I want to now check some other part of the circuit ,
> I have to
> delete the conections to the scope , re-draw them to the new points
> and
> re-run the simulation.
Thats right its crap.
This does not seen correct to me.Other
> simulators(ie
> LTspice) you just move the cursor around the schematic and click where
> you want to see the waveform.
> I am sure Electronics Workbench can do this , but I am sure I am
> overlooking
> something.
I would overlook Multisim completely if I were you. I would suggest
SuperSpice:-)
To view *any* voltage or current in SS, you can do any of the following
1 Place a test point so its pin is on a wire or device pin. Moving the
test point will update the graph to the new signal.
2 Alt-click on a pin or wire to display single signals, ctrl-click to
select multi viewed signals. Or, enable probe mode, then its just a
click.
3 Use the left docked, tabbed workspace window that contains a standard
windows list view of all signals. Click on the signal name. ctrl-click
to multi view. (Just added this one with todays update)
Kevin Aylward
sa...@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.
Tim Stinchcombe
> I have to
> delete the conections to the scope , re-draw them to the new points
> and
> re-run the simulation. This does not seen correct to me.Other
> simulators(ie
> LTspice) you just move the cursor around the schematic and click where
> you want to see the waveform.
> I am sure Electronics Workbench can do this , but I am sure I am
> overlooking
> something.
I stopped using Multisim some months ago, in favour of something more
capable (using SIMetrix AD Plus now). Two suggestions: if your version
allows it, try putting more than one scope on the circuit (Multisim
Professional certainly allows this); or run a more 'traditional' transient
analysis (Simulate, Analyses, Transient Analysis), and specify all you want
to see on the 'Output Variables' tab. Either way, if you want to see more
than you originally asked for, you will have to re-run the analysis (at
least I'm fairly certain of this, but I'm quite willing to be proved
wrong...). Probably like many other simulators (e.g. SuperSpice, as Kevin is
always very quick to point out!), SIMetrix has the ability to 'probe' any
voltage or current *after* the simulation has run - you get so used to doing
this, now that I look back, I'm amazed at how long I put up with Multisim's
inability to do it.
Tim
--
__________________________________________________________
Tim Stinchcombe
Cheltenham, Glos, UK
Fred Bartoli
"Tim Stinchcombe" <tim...@tstinchcombe.freeserve.co.uk> a écrit dans le
message news: bbi8u2$m52$1...@newsg2.svr.pol.co.uk...
<snip>
> now that I look back, I'm amazed at how long I put up with Multisim's
> inability to do it.
>
So did I when I uninstalled it after a painful 2 hours try.
Fred.
Kevin Aylward
>> Now the problem. I want to now check some other part of the circuit ,
>> I have to
>> delete the conections to the scope , re-draw them to the new points
>> and
>> re-run the simulation. This does not seen correct to me.Other
>> simulators(ie
>> LTspice) you just move the cursor around the schematic and click
>> where you want to see the waveform.
>> I am sure Electronics Workbench can do this , but I am sure I am
>> overlooking
>> something.
>
> I stopped using Multisim some months ago, in favour of something more
> capable (using SIMetrix AD Plus now). Two suggestions: if your version
> allows it, try putting more than one scope on the circuit (Multisim
> Professional certainly allows this); or run a more 'traditional'
> transient analysis (Simulate, Analyses, Transient Analysis), and
> specify all you want to see on the 'Output Variables' tab. Either
> way, if you want to see more than you originally asked for, you will
> have to re-run the analysis (at least I'm fairly certain of this, but
> I'm quite willing to be proved wrong...). Probably like many other
> simulators (e.g. SuperSpice, as Kevin is always very quick to point
> out!), SIMetrix has the ability to 'probe' any voltage or current
> *after* the simulation has run
Don't forget SS does, power, gm, vbe, vdsat etc in the same way as
well:-)
The default is to save everything, but you can tell it to just save the
ones you want if its going to be a big file.
>- you get so used to doing this, now
> that I look back, I'm amazed at how long I put up with Multisim's
> inability to do it.
I got used to this indispensable feature in PSpice way back in 87. I
remember scrapping IsSpice around 1990 because it could not do it. I
don't consider it realistic to be able to a design without this feature.
Tim Stinchcombe
> > simulators (e.g. SuperSpice, as Kevin is always very quick to point
> > out!), SIMetrix has the ability to 'probe' any voltage or current
> > *after* the simulation has run
>
> Don't forget SS does, power, gm, vbe, vdsat etc in the same way as
> well:-)
...and a quick headcount in SIMetrix suggests around 40 probe functions are
available, with approx 50 measurement functions that can be taken from
graphs ;-)
> I got used to this indispensable feature in PSpice way back in 87. I
> remember scrapping IsSpice around 1990 because it could not do it. I
> don't consider it realistic to be able to a design without this feature.
I can't claim to be 'a designer', but for the tinkering I do, after having
used such a feature, I certainly wouldn't want to use anything that doesn't
have it.
Tim Stinchcombe
> > inability to do it.
> >
>
> So did I when I uninstalled it after a painful 2 hours try.
LOL! I must have a higher tolerance level (but then I was just starting out
then) - it was several weeks before I decided that it really didn't cut the
mustard, and then it took about another two months before I finally cracked
and demanded my cash back.
rob
> > > I'm quite willing to be proved wrong...). Probably like many other
> > > simulators (e.g. SuperSpice, as Kevin is always very quick to point
> > > out!), SIMetrix has the ability to 'probe' any voltage or current
> > > *after* the simulation has run
> >
> > Don't forget SS does, power, gm, vbe, vdsat etc in the same way as
> > well:-)
>
> ...and a quick headcount in SIMetrix suggests around 40 probe functions are
> available, with approx 50 measurement functions that can be taken from
> graphs ;-)
>
> > I got used to this indispensable feature in PSpice way back in 87. I
> > remember scrapping IsSpice around 1990 because it could not do it. I
> > don't consider it realistic to be able to a design without this feature.
>
> I can't claim to be 'a designer', but for the tinkering I do, after having
> used such a feature, I certainly wouldn't want to use anything that doesn't
> have it.
>
> Tim
So I guess the general feeling is that Multisim is a waste of time.
Pity , they seem to have a nice library of parts to mess around with.
Any good low cost digital simulators out there.I'm happy to use
LTspice
for the analog stuff , but their digital library is pretty
sparce.Electronics
Workbench had a nice "mix" of analog and digital parts, but user
interface seems to suck.
Oh well :0(
Thnks for the info guys.
Rob
Tim Stinchcombe
> So I guess the general feeling is that Multisim is a waste of time.
> Pity , they seem to have a nice library of parts to mess around with.
> Any good low cost digital simulators out there.I'm happy to use
> LTspice
> for the analog stuff , but their digital library is pretty
> sparce.Electronics
> Workbench had a nice "mix" of analog and digital parts, but user
> interface seems to suck.
I suspect that 'low cost' and 'sizeable digital library' are mutually
exclusive. Multisim does have a good number of 4000 and 74 series digital
models, which seems to be quite rare in it's cost bracket. PSpice seems to
have many digital models, but is pricey of course. When I was looking to
replace Multisim, I polled several vendors (as Multisim, all Xspice-based I
believe) in differing price brackets, and asked: how big is your digital
library?; what facilities do you provide for the user to make his own models
if any part is not in the library? They were: Micro-cap, SIMetrix,
SuperSpice, CADMigos, EasySpice, VisualSpice, TINAPro, TopSpice. From the
replies, for my money, SIMetrix was the clear winner (mainly because they
have a nice, simple, proprietary method for coding your own digital models);
one company didn't even reply! (CADMigos); of the others, TINAPro possibly
showed some promise - it implied their library was quite large - however
they are based in Hungary, and after my experience with mediocre support
from EWB, I decided to stick with a native English speaking company.
Terry Pinnell keeps a nice page of links of ECAD packages:
http://www.terrypin.dial.pipex.com/ECADList.html
If you come across a good package, I would be interested to hear about it!
Kevin Aylward
> Hi Rob,
>
>> So I guess the general feeling is that Multisim is a waste of time.
>> Pity , they seem to have a nice library of parts to mess around with.
>> Any good low cost digital simulators out there.I'm happy to use
>> LTspice
>> for the analog stuff , but their digital library is pretty
>> sparce.Electronics
>> Workbench had a nice "mix" of analog and digital parts, but user
>> interface seems to suck.
>
> I suspect that 'low cost' and 'sizeable digital library' are mutually
> exclusive. Multisim does have a good number of 4000 and 74 series
> digital models, which seems to be quite rare in it's cost bracket.
> PSpice seems to have many digital models, but is pricey of course.
> When I was looking to replace Multisim, I polled several vendors (as
> Multisim, all Xspice-based I believe) in differing price brackets,
> and asked: how big is your digital library?;
> what facilities do you
> provide for the user to make his own models if any part is not in the
> library?
Models are a simple text file. e.g.
.SUBCKT D_DividerSub_XN _ssi_pin_in out
*
*The digital frequency divider is a programmable stepdown divider which
*accepts an arbitrary divisor (div_factor), a dutycycle term
(high_cycles), and an initial
*count value (i_count). The generated output is synchronized to the
rising edges of the input
*signal.
a1 _ssi_pin_in out divider
.model divider d_fdiv(div_factor = 5 high_cycles = 3 i_count = 4
rise_delay = 1e-9 fall_delay = 1e-9)
.ends
The parameters are pretty much self explanatory.
They were: Micro-cap, SIMetrix, SuperSpice, CADMigos,
> EasySpice, VisualSpice, TINAPro, TopSpice. From the replies, for my
> money, SIMetrix was the clear winner (mainly because they have a
> nice, simple, proprietary method for coding your own digital models);
Ok...First. The main reason that I dont have a large set of digital
models in my own libary is because I am an analog designer, so dont use
them much. However, I have made analogue and digital models of the main
generic digital types, e.g., d-tpe, j-k, etc. I personally find the
analogue versions more usefull, since my digital bits are usually
minimal.
Second. Actually making XSpice digital models is actually a pretty easy
process. The basic model types already exist, you just customise them a
bit by copying an existing format. The issue is in making 1000's of them
that takes the time.
Complex models can be made with the generic XSpice state machine, I have
a full description here
http://www.anasoft.co.uk/EE/xspicestatemachine/statemachine.html. IMO, I
think I am the only person who has actually went to the trouble of
making such instructions freely available. It took me a bit of work to
decipher what was in the XSpice manual on this.
Lastly, any one who does make a decent set of generic XSpice digital
models for distribution gets a freebee pro gold SS licence.